This invention relates to pressure-sensitive adhesive sheet material, to garment closures made therefrom, and to garments incorporating such closures.
In the past, a wide variety of devices have been used for closing garments, e.g., hooks and eyes, buttons, snaps, zippers, hook-and-loop fasteners, buckles, etc. Each of these devices is useful in appropriate circumstances, but each requires expensive findings, separate operations for attaching the two cooperative parts of the closure, or both. Safety pins are commonly employed in fastening a garment such as a diaper, but they are often inconvenient to apply and are prone to come open and injure the wearer of the garment.
Strips of normally tacky and pressure-sensitive adhesive tape have also been used as means of closure; see, e.g., U.S. Pat. Nos. 3,180,335, 3,630,201, and 3,646,937. The use of pressure-sensitive adhesive tape strips is particularly appealing for "throwaway" items such as nonwoven medical examination robes, temporary lab smocks, disposable diapers, and the like. Such strips, however, must be either cut from a roll at the time of use, provided with a readily removable liner, or both. The first of these techniques is inconvenient and the second involves a liner disposal problem.
The aforementioned U.S. Pat. No. 3,646,937 states that a linered tape strip which protrudes beyond the edge of a diaper prior to use results in inconvenient handling; if the liner inadvertently becomes detached, it may be ingested by the baby, and the adhesive itself may stick to some undesired location. To cope with these problems, the patentee coats pressure-sensitive adhesive on the back of the release liner, thus permanently adhering it to the underside of the diaper border. A pressure-sensitive adhesive strip is then so positioned that one end portion adheres to the upper side of the diaper border, with the remainder of the strip bending around the edge and contacting the release liner. At the time of use, the lower portion of the strip is pulled free from the liner and adhered to the desired location on a juxtaposed or overlapped border of the garment. To prevent the portion of the strip in contact with the liner from pulling free at an inopportune time, a small area of the liner may be modified to provide increased adhesion.
Although the diaper closure just described is not only mechanically effective but also commercially successful, certain problems are associated with its use. For example, it requires the separate application of adhesive to the garment-contacting portion of the liner. Where the closure is used to hold disposable diapers on an active baby, the pressure-sensitive adhesive may span the gap between adjacent borders of a diaper, come in contact with the baby's tender skin and cause irritation.
In summary, tape closures have shown great promise for use on disposable garments, but each of the closures heretofore available has been subject to faults which limited its use.